Adhesives are applied to a substrate and are widely used for various commercial and industrial applications such as product assembly and packaging.
Hot melt adhesives are widely used in the packaging industry to seal cardboard cases, trays and cartons. Some applications require hot melt adhesive with high heat resistance (ability to maintain fiber tear at high temperature) and sufficient strength so that sealed container will not pop open at 125° F.
Hot melt adhesives for assembly and packaging are typically composed of a polymer, a tackifier and a wax. Each component provides a specific function: the base polymer provides cohesive strength and elasticity; the tackifier provides wetting, tack and viscoelastic properties; and the wax helps to moderate viscosity, control setting speed and improve bond strength and temperature resistance.
In recent years, demand for waxes has grown in hot melt adhesive applications and in other fields of applications. With rising crude oil prices, refineries increasingly produce more gasoline and feedstock than highly refined wax, because gasoline and feedstock have higher monetary value and manufacturing efficiency. Instead, refineries tend to produce larger quantities of less refined waxes, which have more oil content and higher levels of contaminants than the highly refined waxes. Use of these less refined waxes in hot melt adhesives decreases the overall performance of the adhesive.
There is a need in the art for a hot melt adhesive that possesses good performances such as high heat resistances that can be prepared with less refined waxes. The current invention fulfills this need.